Phew, this lifehack (stolen from
@domi ) saved my butt so I'm just going to share it further.
Sure, it looks awful... but if you have windows facing south (or if you can't afford/your landlord doesn't allow you to mount sun-blocking curtains) this is a lifesaver.
In the current heatwave my apartment (according to temperature sensor on my desk) was already hitting 36*C inside despite window in the room being covered with a blanket. Standing in the kitchen in the afternoon made me feel dizzy within two minutes.
After applying the tinfoil to windows in the kitchen, over the few hours temperature dropped to 28*C. Tinfoil is so hot, that I can't keep my hand on the window for more than 4 seconds (so it's very close to 50*C).
Going to apply the tinfoil to the window in the room as well, it should reflect a lot of that heat and make blanket much colder as a result.
Something something Linux users don't need windows or something